JP7069509B2 - Equipment and firing method for cell firing of solid oxide fuel cells - Google Patents

Description

This specification claims the benefit of priority based on Korean Patent Application No. 10-2018-097787 filed with the Korean Patent Office on August 22, 2018, and is disclosed in the document of the Korean patent application. All content is included as part of this specification.

The present invention relates to a cell firing device and a firing method for a solid oxide fuel cell. More specifically, the solid oxide capable of calcining and main sintering using one device by adjusting the height of the setter. The present invention relates to a cell firing device and a firing method for a fuel cell.

A fuel cell is a device that directly converts the chemical energy of fuel and air into electricity and heat by an electrochemical reaction. Unlike existing power generation technologies that take the process of burning fuel, generating steam, driving turbines, and driving generators, fuel cells are not only highly efficient because they have no combustion process or drive, but also the environment. Such a fuel cell, which does not induce a problem, emits almost no air pollutants such as SOx and NOx, generates less carbon dioxide, is a pollution-free power generation, and has advantages such as low noise and no vibration.

Examples of the fuel cell include a phosphoric acid fuel cell (PAFC), an alkaline fuel cell (AFC), a polymer electrolyte fuel cell (PEMFC), a direct methanol fuel cell (DMFC), and a solid oxide fuel cell (SOFC). Among these, the solid oxide fuel cell has a high power generation efficiency because it has a low overvoltage and a small irreversible loss based on a low activation polarization. Further, since not only hydrogen but also carbon or hydrocarbon-based substances can be used as fuel, the range of fuel selection is wide and the reaction rate at the electrode is high, so that an expensive noble metal is not required as an electrode catalyst. Moreover, the heat emitted from power generation has a very high temperature, so its utility value is high. The heat generated from the solid oxide fuel cell can be used not only for fuel reforming but also as an energy source for industrial use and cooling in thermal combined power generation.

To explain the basic operating principle of a solid oxide fuel cell (SOFC), a solid oxide fuel cell is basically a device that generates power through an oxidation reaction of hydrogen, and is an anode of a fuel electrode and air. At the cathode of the pole, the electrode reaction as shown in the following reaction formula 1 is performed.

[Reaction equation 1]
Air electrode: (1/2) O ₂ + ^2e- → O ^2-
Fuel electrode: H ₂ + O ^2- → H ₂ O + ^2e-
Overall reaction: H ₂ + (1/2) O ₂ → H ₂ O

That is, the electrons reach the air electrode via an external circuit, and at the same time, the oxygen ions generated at the air electrode are transmitted to the fuel electrode through the electrolyte, and at the fuel electrode, hydrogen combines with the oxygen ions to form electrons and water. In a solid oxide fuel cell, a dense electrolyte layer and a porous air electrode layer and a fuel electrode layer are formed as electrodes with the electrolyte layer in between, and the electrode reaction is an electrolyte layer. It occurs at the interface between the fuel cell and the electrode layer.

When manufacturing a cell of such a solid oxide fuel cell, a laminated body in which two or more layers made of different substances are joined is fired to make a product, and since each layer has a different shrinkage rate and a coefficient of thermal expansion, it is fired. It has the characteristic of sometimes bending. If such a bending phenomenon occurs, it cannot be manufactured as a product. When such a bending phenomenon occurs, there is a problem that the stress applied to the cell becomes large, the defective rate of the product becomes high, and another flattening step is required after firing.

Therefore, in order to produce a high-quality product, there is a need for a cell firing device and a firing method for a solid oxide fuel cell that can solve the bending phenomenon that occurs during firing and obtain a flat cell.

The present invention has been derived in order to solve the above-mentioned problems, and an object of the present invention is to adjust the height of a plurality of setters according to the process conditions and to adjust the height of a plurality of setters to each other when manufacturing a cell of a solid oxide fuel cell. Provided are a cell firing device and a firing method for a solid oxide fuel cell capable of simultaneously performing a firing and flattening step of a laminate in which two or more layers made of different substances are joined without performing the firing and flattening steps in two steps. It is in.

The cell firing apparatus for a solid oxide fuel cell according to an embodiment of the present invention includes a plurality of setters that support the laminate, and a pair of supports that are combined with the setters to support the setters. The materials on both sides are different from each other, and the height can be adjusted according to the support.

In one embodiment, the setter located at the lowermost end is characterized in that both sides are made of the same material.

In one embodiment, the setter is characterized in that one side is made of a material that is not reactive with an electrolyte and the other side is made of a material that is not reactive with an anode.

In one embodiment, the laminate comprises an anode and an electrolyte.

In one embodiment, the setter is characterized by containing a dense ceramic material on one side and a porous ceramic material on the other side.

In one embodiment, the dense ceramic material comprises an alumina ceramic material, wherein the porous ceramic material comprises one or more of a porous alumina ceramic and a silicon carbide (SiC) ceramic.

The method for firing a cell of a solid oxide fuel cell according to an embodiment of the present invention is a step of arranging a laminate on a plurality of setters coupled to a pair of supports of a device for firing a cell of a solid oxide fuel cell. After adjusting the height of the setter so as to be separated from the laminate, the step of primary firing the laminate, and adjusting the height of the setter to be equal to or lower than the height of the laminate, the laminate It is characterized by including a step of secondary firing.

In one embodiment, the primary firing step is characterized in that the laminate bends toward the top surface.

In one embodiment, in the step of secondary firing, the setter pressurizes the laminate so that the cell of the fuel cell has a flat shape.

In one embodiment, the setter is not fixed to the support in the step of secondary firing.

According to the present invention, the height of a plurality of setters is adjusted according to the conditions of the two heat treatment steps, and two or more layers made of different substances are joined to each other when the cell of the solid oxide fuel cell is manufactured. There is an effect that the firing and flattening steps can be performed simultaneously without performing the firing and flattening steps in two steps.

In addition, since the heat treatment process can be reduced by simultaneously performing the firing and flattening processes, not only the process time and cost can be saved, but also the size and thickness can be easily adjusted, and the cells can be formed uniformly. This has the effect of lowering the defective rate of products, improving productivity, and facilitating mass production.

It is sectional drawing of the cell firing apparatus of a solid oxide fuel cell according to one Embodiment of this invention. (A) is a sectional view of a cell firing apparatus for a solid oxide fuel cell according to an embodiment of the present invention at the time of the primary firing step (temporary sintering), and (b) is a secondary firing step (main sintering). It is sectional drawing of the cell firing apparatus of the solid oxide fuel cell according to one Embodiment of this invention at the time.

The present invention will be described in detail with reference to the accompanying drawings. Here, repeated explanations and detailed description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted. Embodiments of the invention are provided to more fully explain the invention to those with average knowledge in the art. Therefore, the shape and size of the elements in the drawings may be exaggerated for a clearer explanation.

When a part of the specification "contains" a component, this does not exclude other components unless otherwise stated, and may further include other components. Means.

In the following, preferred embodiments are presented to aid in understanding the invention. However, the following embodiments are provided only for easier understanding of the present invention, and the contents of the present invention are not limited by the following embodiments.

<Equipment for firing cells of solid oxide fuel cells>

FIG. 1 is a cross-sectional view of a cell firing device for a solid oxide fuel cell according to an embodiment of the present invention.

The cell firing device for a solid oxide fuel cell according to the present invention can include a setter 10 and a support 20.

The setter 10 has a structure that supports the laminated body, and a plurality of setters 10 can be provided. The laminate is a laminate of an anode and an electrolyte of a solid oxide fuel cell, and the setter 10 is a ceramic plate used when the laminate is to be fired. It is possible to prevent deformation of the object to be fired and maintain electrical properties through uniform heat transfer. The setter 10 according to the present invention can be provided so that the materials on both sides are different from each other.

In one embodiment, the setter 10 can be made of a material in which one surface 10a is non-reactive with an electrolyte and the other surface 10b is non-reactive with an anode. At this time, one surface 10a of the setter is a surface in contact with the electrolyte of the laminate and can support the laminate, and the other surface 10b of the setter is a surface in contact with the anode of the laminate and supports the laminate. Means the opposite side.

Here, the setter 10 can include a ceramic material, one side 10a can contain a dense ceramic material, and the other side 10b can contain a porous ceramic material. More specifically, one side 10a may contain a dense alumina ceramic material, and the other side 10b may contain any one of a porous alumina and silicon carbide (SiC) ceramic material.

During the primary firing (temporary sintering) process, a binder-burn out phenomenon occurs in which the organic matter existing in the laminated body burns, and the bending phenomenon of the laminated body occurs while the organic matter burns.

Since the porous ceramic material is contained in the other surface 10b of the setter, the effect that the gas generated in the binder burnout process and the firing process of the laminate smoothly escapes and the laminate does not crack is generated. Further, the porous ceramic setter 10b has an effect that a uniform fired body can be obtained because the laminated body is not adhered or adhered to the surface of the setter before the binder or the like is burned out.

Further, since the setter 10a contains a dense ceramic material, the setter 10 and the electrolyte of the laminate are prevented from reacting with each other, and the electrolyte prevents the setter 10a from being damaged during the secondary firing. be able to.

The number of setters 10 according to the present invention may be plural, and among them, the setter 10 located at the lowermost end of the cell firing device of the solid oxide fuel cell is made of the same material on one side and the other side. May be good. Since the setter 10c located at the lowermost end can support the laminate, it can contain a porous ceramic material that does not react with the anode.

The support 20 can be combined with a plurality of setters 10 to support the setter 10. The supports 10 can be provided as a pair by being located on the corresponding sides of the setter 10.

The support 20 is provided in the form of a screw and thus can be screwed to the setter 10. At this time, the setter 10 may further include a coupling portion (not shown) on the corresponding side surface in order to couple with the support 20.

Further, the position of the setter 10 can be adjusted according to the support 20, and the height between the setters 10 can be adjusted according to the firing step.

When the bending phenomenon of the laminated body occurs due to the binder burnout in the primary firing step, the position of the setter 10 is adjusted to prevent the setter 10 from pushing the laminated body, and the height between the setters 10 is adjusted. It can be formed higher than the flatness. At this time, the flatness means that when the laminated body after firing is placed on a flat bottom, the cell is flat as the value is closer to 1 when the laminated body is bent and the highest point is divided by the cell thickness. It can be said that there is.

In the flattening step, which is a secondary firing step, a weight must be applied to the laminated body and pressure must be applied in order to flatten the laminated body in which the bending phenomenon has occurred. Therefore, the position of the setter 10 can be adjusted so that the setter 10 comes into contact with the laminate and applies pressure.

Further, any one of the setter 10 and the support 20 may further include a fixing portion (not shown) for fixing the position of the setter 10.

<Sell firing method for solid oxide fuel cells>

FIG. 2A is a sectional view of a cell firing apparatus for a solid oxide fuel cell according to an embodiment of the present invention at the time of the primary firing step (temporary sintering), and FIG. 2B is a secondary firing step. It is sectional drawing of the cell firing apparatus of the solid oxide fuel cell according to one Embodiment of this invention at the time of (this sintering).
The cell firing method for a solid oxide fuel cell according to the present invention includes a primary firing step (S100) and a secondary firing step (S200), where the secondary firing step (S200) is a flattening step.

The primary firing step (S100) is a step (S110) in which the laminate is placed on each of the plurality of setters 10 coupled to the pair of supports 20, and the height of the setter 10 is adjusted so as to be separated from the laminate. After that, the step (S120) of firing the laminated body can be included.

The primary firing step (S100) is a step during or after the binder burnout process in which the organic matter existing in the laminated body burns and the binder burnout process. At this time, the primary firing step is performed in the range of 200 ° C to 600 ° C.

Then, in the primary firing step, a bending phenomenon occurs due to the difference in the coefficient of thermal expansion of each of the configurations constituting the laminated body, and the laminated body bends toward the upper surface. At this time, the upper surface of the laminated body means a surface that does not come into contact with the setter 10 and that comes into contact with the setter 10 during the secondary firing described later.

Since cracks may occur in the laminate if physical pressure is applied when the laminate bends, the height between the setters 10 must be formed higher than the flatness of the laminate in the primary firing step.

The secondary firing step is a step of flattening the laminated body bent by the primary firing, and is a step of adjusting the height of the setter 10 to be equal to or lower than the height of the laminated body and then increasing the temperature to fire the laminated body. Is.

Here, the height of the laminated body means the difference between the highest point and the lowest point of the curved laminated body which is changed by the primary firing. By adjusting the height between the setters 10 to be equal to or lower than the height of the laminate, the setter 10 applies a constant pressure equal to or higher than the yield point to the laminate in response to the heat of the laminate lowering the yield point. Can be flattened.

At this time, in the secondary firing step, the laminated body can be fired in a temperature section in the range of 500 ° C. to 1500 ° C. When the firing temperature is 500 ° C or higher, there is an effect that flattening is possible with a low weight, and when the firing temperature is 1500 ° C or lower, flattening must be performed with a high weight, but it is more precise. It has the effect of being able to obtain an electrolyte.

The setter 10 does not have to be fixed to the support 20 in order to apply pressure to the laminate via the setter 10. That is, when the setter 10 is not fixed to the support 20, the setter 10 applies pressure to the laminated body by gravity, and the pressure can be applied without separating from the laminated body even during the process of flattening the laminated body. ..

At this time, when the setter 10 contains one material, in one embodiment, when the setter 10 contains a porous ceramic material, the anode of the laminate and the other surface 10b of the setter come into contact with each other in the secondary firing step and the setter. There arises a problem that the laminated body reacts with 10. Then, one firing device goes through the primary and secondary firing steps, and there may be a problem that the production quality is deteriorated due to the difference in temperature and pressure between the two firing processes.

Therefore, one surface of the setter 10 and the other surface 10b in contact with the anode of the laminate may contain a porous ceramic material that does not react with the anode, and one surface 10a may contain a dense ceramic material that does not react with the electrolyte.

The method for firing a cell of a solid oxide fuel cell according to the present invention further includes a step of manufacturing a cell of the solid oxide fuel cell by printing a cathode on the electrolyte surface after firing the laminate. be able to.

Although the above description has been made with reference to the preferred embodiments of the present invention, those skilled in the art will be skilled in the art without departing from the ideas and areas of the present invention described in the claims below. It will be appreciated that the present invention can be modified and modified in various ways.

Claims (8)

Includes a plurality of setters configured to support the laminate containing the anode and electrolyte , and a pair of supports coupled with the setter to support the setter.
The materials on both sides of the setter are different from each other.
The height can be adjusted according to the support.
One surface of the setter is a surface of the laminate that comes into contact with the electrolyte and supports the laminate.
The other surface of the setter is the surface of the laminate that comes into contact with the anode and comprises a porous ceramic material.
The other side of the setter includes an opposite side that supports the laminate.
The setter located at the lowermost end is made of the same material on both sides.
A device for firing cells of solid oxide fuel cells. The setter is
One side is made of a material that is not reactive with the electrolyte.
The other surface is made of a material that does not react with the anode.
The device for firing a cell of a solid oxide fuel cell according to claim 1. The setter is
One side contains a dense ceramic material,
The other side contains a porous ceramic material,
The device for firing a cell of a solid oxide fuel cell according to claim 1 or 2 . The dense ceramic material includes an alumina ceramic material.
The porous ceramic material comprises one or more of a porous alumina ceramic and a silicon carbide (SiC) ceramic.
The device for firing a cell of a solid oxide fuel cell according to claim 3 . A step of arranging each laminate on a plurality of setters coupled to a pair of supports of the cell firing device of the solid oxide fuel cell according to any one of claims 1 to 4 .
After adjusting the height of the setter so as to be separated from the laminate, the step of primary firing the laminate, and after adjusting the height of the setter to be equal to or lower than the height of the laminate, the laminate Including the step of secondary firing,
A method for firing a cell of a solid oxide fuel cell. In the step of primary firing,
The laminate bends toward the top surface,
The method for firing a cell of a solid oxide fuel cell according to claim 5 . In the step of secondary firing,
The setter pressurizes the laminate so that the cell of the solid oxide fuel cell has a flat shape.
The method for firing a cell of a solid oxide fuel cell according to claim 5 or 6 . In the step of secondary firing,
Do not fix the setter to the support,
The cell firing method for a solid oxide fuel cell according to any one of claims 5 to 7 .

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